A conventional testing apparatus used to verify the performance of a vehicle engine is provided with a dynamometer 52 connected to an output shaft of an engine under test 50 as an object to be tested via a coupling 51 as shown in FIG. 9. In this type of the testing apparatus, working load evaluation of the engine under test 50 is performed by reproducing the inertia equivalent weight, the frictional resistance, and the running resistance of a vehicle drive system by the load control of the dynamometer 52. Generally, the control of the dynamometer 52 of such a testing apparatus is performed by comparing the torque of the engine under test 50 measured by an axial torque meter with a target torque such that the measured torque corresponds to the target torque.
Patent Document 1 proposes another conventional engine testing apparatus. In the testing apparatus, the control of the engine under test 50 is performed by feedforward control of the throttle opening degree by an opening degree command. In contrast, the control of the dynamometer 52 is performed by feedforward control that brings an obtained torque signal of the engine under test 50 into a target torque signal, and feedback control that corrects the target torque according to the rotation speed of the engine under test 50.